[ARC5] IFF Sets

[Mike Everette]

APX-15... are you sure it was not an APS-15?  (Yes, I know the difference between the two designations, in the JAN system.)

I ask, because among my dad's WW2 radio and radar school notes is a folder on the AN/APS-15A which was an add-on for the SCR-717 system.  I have not looked at this material in a really long time, and it would take some time to find it among my "library," but I recall that this was described as a blind-bombing device.

This folder consists mostly of hand written class notes, with a few printed sheets.  It's nowhere near as comprehensive as his material for the SCR-717, which takes up the major portion of his radar school manual.

Dad was trained to work on B-29 equipment and deployed to the CBI in the fall of 1944.  If there was an APX-15 system it would seem logical that he would have been trained on it before leaving the States... maybe, anyway. When the B-29s moved to the Pacific he stayed behind in India to work on AI and IFF gear, much of it on night fighters (both US and British a/c as he was on a joint base), but also installing equipment on B-24s on their way to China.  He apparently ended up with a lot of time on his hands and actually spent a lot of it flying the Hump as a radio operator on C-46s.

73

Mike
W4DSE

--- On Sun, 12/23/12, Mike Morrow <kk5f at earthlink.net> wrote:

> From: Mike Morrow <kk5f at earthlink.net>
> Subject: [ARC5] IFF Sets
> To: arc5 at mailman.qth.net
> Date: Sunday, December 23, 2012, 1:19 PM
> Jeep wrote:
> 
> > ...the current system for MIL is pretty much the same,
> with Mode 2/B
> > being the mil only discreet codes for air defense
> uses.  The Civil
> > Mode A (mode 1)  and C (mode 3) are used, with
> mode C including your
> > altitude info (via an encoder).
> 
> Then in the 1960s, the military added Mode 4.  The late
> Vietnam-era AN/APX-72
> included Mode 4, but a KIT-1A/TSEC encoding "computer" was
> required to be
> attached.  The AN/APX-72 is doubtless flying still
> today...and swimming as
> well.  My missile submarine used the AN/APX-72 as its
> IFF set for (very rare)
> work with aircraft.  Its fuses were normally pulled to
> prevent unintended
> transmission from the unit.  It got the Communications
> officer on my sub fired
> when it was determined he had gotten one day ahead of where
> he should have
> been in the daily destruction of the coding cards.
> 
> In my collections, I find the old RT-82/APX-6 to be a far
> more interesting
> piece of hardware than the RT-859A/APX-72.  :-)
> 
> I also have the ABK-* IFF (a.k.a. the SCR-595-A) and the
> SCR-695-A IFF (a.k.a.
> the ABF-*).  I'd like to find a complete (with original
> tubes) AN/APX-2
> someday, as well as a AN/APX-44.
> 
> There was an interesting IFF set of a sort designed to add
> on to the AN/APQ-13
> bombing radar on B-29s called the AN/APX-15.  It
> produced a warning display
> when radar return that was characteristic of the propellars
> of certain classes
> of Japanese aircraft was detected.  I don't know if any
> were ever deployed.
> 
> Mike / KK5F
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